A new system approach to the identification and systematization of geophysical pulses is described. It includes stages of detection, analysis, object and structural description, pulse classification. In order to identify the pulses in geoacoustic emission, we apply a method based on the calculation of adaptive threshold, the values of which are estimated by the results of signal root-mean-square deviation in a moving window of a defined size. The detected pulses are described and identified by an adaptive matching pursuit algorithm which allows us to decompose the pulse into linear combination of basic functions from a combined Gauss-Berlage dictionary with minimum spatial and time costs and with the required accuracy of constructed approximations. Within the framework of object approach, pulses are described by a combination of features such as the number of functions in a decomposition, function type, parameters etc. We present a method of reduction of innumerable diversity of identified pulses to a denumerable set of patterns. It is based on structural transformation of geoacoustic emission pulses with simultaneous automatic procedure of classification. The results obtained during the application of the described system approach to the analysis of geoacoustic signals are summarized in a Geophysical Signal Catalogue.

Статья посвящена математическому моделированию областей повышенных деформаций земной коры, возникающих при подготовке камчатских землетрясений. Для этого произведено обобщение классической модели косейсмических деформаций земной коры, которое заключалось во введении повышающих коэффициентов, зависящих от эффективности снятия энергии упругих деформаций. На основании разработанной модели произвдено моделирование полей деформации, возникающих при подготовке двух камчатских землетрясений. Показано, что области повышенных деформаций распространяются на сотни километров от очагов готовящихся землетрясений как на поверхности земной коры, так и в ее толще. The article is devoted to mathematical modeling of increased deformations areas of the Earth’s crust that occur during the preparation of Kamchatka earthquakes. For this purpose, a generalization of the classical model of the Earth’s crust co-seismic deformations, proposed by Yu. Okada, was made. The generalization is consisted in the introduction of increasing coefficients depending on the seismic efficiency. Based on the developed model, the deformation fields, that occurred during the preparation of two Kamchatka earthquakes, were simulated. It is shown that the areas of increased deformations extend hundreds of kilometers from the sources of upcoming earthquakes both on the surface of the Earth’s crust and in its thickness.

In seismically active regions of the Earth, to which the Kamchatka peninsula refers, pre-seismic anomalies are recorded in different geophysical fields. One of such fields is the acoustic emission of rocks, the anomalies of which are recorded 1–3 days before earthquakes at the distance of the first hundreds of kilometers from their epicenters. Results of joint acoustic-deformation measurements showed that growth of geoacoustic radiation intensity occurs during the increase in the level of deformations in rock masses by more than one order compared to the background values. Simulation studies of the areas with increased deformation are realized to understand the causes of anomalous acoustic-deformation disturbance occurrences before strong earthquakes. The model is based on the assumption that the Earth’s crust in the first approximation can be considered as a homogeneous isotropic elastic half-space, and an earthquake source can be considered as a displacements along a rectangular fault plane. Based on these assumptions, deformation regions of Earth’s crust were modeled during the preparations of two earthquakes with local magnitudes ML≈5 occurred on the Kamchatka Peninsula in 2007 and 2009. The simulation results were compared for the first time with the data of a laser strainmeter-interferometer installed at the Karymshina observation site (52.83∘ N, 158.13∘ E). It was shown that, during the preparation of the both earthquakes, the Karymshina observation site was within the region of shear deformations ≈10−7, which exceeded the tidal ones by an order. On the whole, simulation results corresponded to the results of the natural observations. Construction of an adequate model for the generation of acoustic-deformation disturbances before strong earthquakes is topical for the development of an early notification system on the threat of catastrophic natural events.

Представлено сравнительное моделирование зон относительных сдвиговых деформаций для четырех камчатских землетрясений с Mw ≥ 4.8, произошедших в период с декабря 2018 г. по март 2021 г., основанное на статической модели деформационного поля в рамках теории упругости. Земная кора рассмотрена как однородное изотропное упругое полупространство, в котором присутствуют различные источники напряжения, описывающие очаг землетрясения: точечный источник в виде единичной силы, точечный источник в виде комбинации девяти двойных сил, распределенный источник в виде прямоугольной площадки. We present a comparative modeling of the zones of relative shear deformation for four Kamchatka earthquakes Mw≥4.8 that occurred between December 2018 and March 2021. Modeling based on a static model of the deformation field in the framework of the theory of elasticity. The Earth’s crust is considered as a homogeneous isotropic elastic half-space, in which there are different sources of stress describing the source of the earthquake: a point source in the form of a single force, a point source in the form of a combination of nine double forces, a distributed source in the form of a rectangular area.

Статья посвящена построению математической модели высокочастотной (от единиц до десятков килогерц) геоакустической эмиссии приповерхностных осадочных пород, регистрируемой на Камчатке. В основе модели лежит система связанных осцилляторов. Каждый осциллятор описывает дислокационный источник геоакустической эмиссии. Модель строится на основании предположения, что взаимодействие между источниками осуществляется только через излучение. В работе рассматриваются два взаимодействующих между собой дислокационных источника геоакустической эмиссии. Математическое описание этих источников представлено в виде системы двух дифференциальных уравнений второго порядка. Методом Розенброка найдены численные решения модели при различных значениях коэффициента связи между источниками, построены расчетные осциллограммы, спектры и фазовые траектории. Анализ решений показывает, что при увеличении коэффициента связи наблюдается устойчивый обмен энергией между осцилляторами. The article is devoted to mathematical modeling of high-frequency (from units to tens of kilohertz) geoacoustic emission of near-surface sedimentary rocks recorded in Kamchatka. Dislocation emission sources are located in the volume of rocks bounded by a hemisphere of radius 37 m centered at the registration point. A typical signal of high-frequency geoacoustic emission is a combination of relaxation pulses. These pulses are closest in shape to the Berlage pulses. The article proposes a mathematical model of high-frequency geoacoustic emission of near-surface sedimentary rocks in the form of a system of coupled oscillators. Each oscillator describes a dislocation source of geoacoustic emission. The interaction between the sources is carried out only through radiation. A system of two coupled oscillators is considered. The Rosenbrock method was used to find numerical solutions for different values of the coupling coefficient between sources. Oscillograms, spectra and phase trajectories of the process under consideration are constructed. An analysis of the solutions showed that as the coupling coefficient increases, a stable energy exchange between the oscillators is observed.